Industrial dishwasher

ABSTRACT

An industrial dishwashing machine with at least one essentially closed water circuit in which washing water is circulated, and with at least one water inflow which makes rinsing water available which is received into the water circuit after a rinsing operation following a washing operation. An air circuit is provided for drying the batchwith the air circuit being dehumidified by means of the water of the water inflow.

BACKGROUND OF THE INVENTION

[0001] The invention relates to an industrial dishwashing machine withat least one essentially closed water circuit in which washing water iscirculated.

[0002] Industrial dishwashing machines of this type usually performabout 30 to 200 work cycles a day, a work cycle lasting about 1 to 2minutes. In contrast to this, a domestic dishwashing machine is in useonly about one to 3 times a day, the washing duration being about onehour here. In known industrial dishwashing machines, a work cyclecomprises, as a rule, a washing stage, a rinsing stage, and what isknown as a drying operation. On opening of the industrial dishwashingmachine after the drying operation, in order to remove the batch,results in the steam formed in the washing compartment during the dryingoperation escaping into the surroundings. One disadvantage of this isthat a hot humid climate occurs in the workspace in which thedishwashing machine is standing and becomes more extreme with each workcycle of the dishwashing machine. Furthermore, whenever the dishwashingmachine is opened after the drying operation, a large quantity of energyis released, which is not available for further work cycles.

[0003] GB 2 030 446 A discloses a continuously operating dishwashingmachine, in which a batch is delivered on one side and is transportedthrough the entire dishwashing machine via a conveyer belt, so that itis discharged on the other side after the rinsing operation. Thispublication discloses, furthermore, a suction extraction device for thesuction extraction of hot humid air, this air being cooled anddehumidified in a heat exchanger device, whereupon it is discharged asspent air into the surroundings.

[0004] An object of the present invention is to make available anindustrial dishwashing machine, in which the formation of a hot humidclimate in the surroundings is avoided as efficiently as possible, butat the same time an effective drying operation becomes possible. Anobject of the present invention is, furthermore, to make available acorresponding method.

[0005] Further details of the invention are described, with reference toexemplary embodiments illustrated diagrammatically, in the drawing, inwhich:

[0006]FIG. 1 shows a diagrammatic illustration of an industrialdishwashing machine with an air circuit, and

[0007]FIG. 2 shows a diagrammatic illustration of a further industrialdishwashing machine with an air circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0008]FIG. 1 illustrates a diagrammatic view of an industrialdishwashing machine 1. The dishwashing machine 1 comprises essentially awashing compartment 2, in which the batch, not illustrated, is arranged,a water circuit 6, a water inflow 12, a water outflow 11 and an aircircuit 21. A complete work cycle of the dishwashing machine 1 consistsessentially of three successive cycles. These are the washing cycle,rinsing cycle and drying cycle. The washing cycle involves mainly thewater circuit 6, the rinsing cycle is carried out essentially by meansof the water inflow 12, and, in the drying cycle, the water inflow 12and the air circuit 21 cooperate. The batch is arranged in the washingcompartment 2 between washing arms 3. Below the batch and the washingarms 3 is arranged a tub 4 which conducts the water present in thewashing compartment 2 into a tank 5. The tank 5 belongs to the watercircuit 6, in which the washing water 7 required for a washing operationis circulated. During the washing operation, water is extracted from thetank 5 via a line 8 and is led to a pump 9. The washing water 7 is ledfrom the pump 9 via lines 10 to the washing arms 3 and is sprayed intothe washing compartment 2 by these. In the washing compartment 2, thewashing water 7 then runs into the tank 5 again via the tub 4. The watercircuit 6 also contains further components, not illustrated, such as,for example, a device for adding washing agent, heating for heating thewashing water, a cleaning device for the washing water and sensors.Furthermore, a water outflow 11, via which washing water 7 can bedischarged, is connected to the tank 5. For example, after each washingcycle, some of the washing water 7 is discharged via the water outflow11. The tank 5 is filled up with the aid of the water inflow 12 whichmakes available rinsing water 13 which is supplied to the tank 5 via thetub 4 after the rinsing operation. The water inflow 12 is connected to awater source, not illustrated, via a line 14. The line 14 leads via aninflow 15 into a dehumidifier 16 which is filled with water 13 to aheight H. The dehumidifier 16 is connected via an outflow 17, by meansof a line 18, to a heating element 19 which heats the water 13 to atemperature of about 65° C. to 85° C. During the rinsing cycle, theheated rinsing water 13 is led from the heating element through a line20 to the washing arms 3, via which it is distributed to the batch. Thewashing water is distributed in the washing compartment via the washingarms 3 by means of washing nozzles.

[0009] According to a design variant which is not illustrated, thedistribution of the rinsing water takes place via rinsing arms and/orrinsing nozzles, the washing arms and rinsing arms or the washingnozzles and rinsing nozzles being different components. According to thedesign variant which is not illustrated, therefore, the washing cycleand the rinsing cycle take place via two separate systems.

[0010] As already described above, the rinsing water 13 is supplied tothe tank 5 via the tub 4 and thus becomes washing water 7. Furthermore,the dishwashing machine 1 comprises the air circuit 21 which is activeduring a drying cycle. The washing compartment 2 is connected to thedehumidifier 16 via a line 22, the line 22 being led to a distributor 23which is arranged in the interior 24 of the dehumidifier 16 below awater level 25. Air 26, which is led in the line 22 from the washingcompartment 2 to the dehumidifier 16, emerges from the distributor 23and is led out of the dehumidifier 16 via an air line 27 to a fan 28which ensures a flow of the air 26 clockwise through the air circuit 21.The fan 28 is connected via an air line 29 to heating, in which the air26 is heated before it passes through the air line 31 into the washingcompartment 2, flows through the latter and leaves again via the airline 22. The drying cycle is described in detail again below. After therinsing cycle, the moist supersaturated air (approximately 60° C.,approximately 100% relative air humidity or an absolute air humidity ofapproximately 160 g/kg) is sucked out of the washing compartment 2 viathe air line 22 and is dehumidified or cooled in the dehumidifier 16.Dehumidification or cooling takes place as a result of direct contact ofthe air 26 with the cold rinsing water 13 in which the air 26 rises. Thedehumidified and cooled air (approximately 30° C., approximately 100%relative air humidity or approximately 30 g/kg absolute air humidity) isextracted from the dehumidifier 16 via the air line 27 and is blown bythe fan 28, via the air line 29, into the heating 30. Here, the air isheated to approximately 140° C. (approximately 1.2% relative airhumidity or approximately 130 g/kg absolute air humidity) and is blowninto the washing compartment 2 via the air line 31. In the washingcompartment 2, this air is mixed with the supersaturated air present inthe washing compartment and is thus saturated. Via the air circuit 21,the air 26 can be circulated once or more than once as required, andthus dehumidified. The fresh water 13 which is required for each rinsingcycle is preheated via the dehumidifier 16 which is designed as a heatexchanger and in which the air is cooled. The fresh water 13 serves as acooling medium for the air 26. This preheating of the fresh water 13taking place in the dehumidifier 16 is carried out before the freshwater is heated to about 65° C. (for glass washing machines) or 85° C.(for utensil washing machines) in the heating 19 designed as a boiler.The fan 28 may be arranged in the air circuit 21 between washingcompartment 2 and dehumidifier 16 or dehumidifier 16 and heating 30 orheating 30 and washing compartment 2. About 2 minutes are provided forthe drying cycle. According to a design variant, the fan 28 continues torun, with the heating 30 switched off, even after the conclusion of thedrying cycle. An effect of drying or cooling the batch located in thewashing compartment 2 is thereby achieved. In order to retain the energyacquired from the moist drying air 26 optimally for the following workcycle of the dishwashing machine 1, there is provision for insulatingthe dehumidifier 16, the lines 27, 29 and the fan 28.

[0011]FIG. 2 illustrates a variant of the industrial dishwashing machine1 illustrated in FIG. 1. The dishwashing machine 40 illustrated in FIG.2 differs from the dishwashing machine 1 illustrated in FIG. 1 in aparallel connection of the heating 30 and of the dehumidifier 16 in theair circuit 21. The air stream which leaves the washing compartment 2via the air line 22 is divided at a branch point 41. Part of the airstream is led through the dehumidifier 16 and is dehumidified and cooledhere to approximately 30° C. and approximately 100% relative airhumidity or approximately 30 g/kg absolute air humidity. The other partis led via the heating 30 and is heated there to approximately 140° C.(approximately 5.4% relative air humidity or approximately 160 g/kgabsolute air humidity). The two air streams are combined again at asecond branch point 42. This results, on the precondition that the airstreams have been divided in the ratio of 1:1, in an air temperature ofabout 91° C. with 17% relative air humidity or 96.5 g/kg absolute airhumidity. This mixed air is blown into the washing compartment 2 againvia the air line 31. It is possible, via a valve 43 arranged upstream ofthe dehumidifier 16, to set the mixture ratio of the two air streamsrunning parallel.

[0012] The invention is not restricted to exemplary embodimentsillustrated and described. On the contrary, it embraces developments ofthe invention within the scope of the patent claims. In particular, theinvention also provides for designing the air circuit as an opencircuit, in which the air extracted from the washing compartment isconducted, after dehumidification or cooling, into the surroundings andheated surrounding air is returned into the washing compartment. Thereis provision, furthermore, for designing the dehumidifier or heatexchanger in such a way that the media, air and water, have no directcontact in the latter.

What is claimed is:
 1. An industrial dishwashing machine having awashing compartment with at least one essentially closed water circuitin which washing water is circulated, and with at least one water inflowwhich makes available rinsing water which is received into the watercircuit after a rinsing operation following a washing operation, whereinan air stream generating device for drying a batch arranged in thewashing compartment is provided and wherein said air stream circulatesin a closed air circuit and is dehumidified in a dehumidifier whichcontains rinsing water.
 2. The dishwashing machine as claimed in claim1, wherein the dehumidifier is a direct heat exchanger in which themedia are mixed and unmixed.
 3. The dishwashing machine as claimed inclaim 1, wherein the dehumidifier is a cooling register having aclosed-off container with an inflow and an outflow.
 4. The dishwashingmachine as claimed in claim 1, wherein the dehumidifier is an indirectheat exchanger through which the media flow in closed line systems. 5.The dishwashing machine as claimed in claim 1, wherein an air circuit isactive when the water and/or the water inflow is/are at rest.
 6. Thedishwashing machine as claimed in claim 5, wherein the air circuitcomprises at least one fan and/or, one heating element and/or, at leastone valve.
 7. The dishwashing machine as claimed in claim 1, wherein thedehumidifier and the heating element are arranged in series in the aircircuit.
 8. The dishwashing machine as claimed in claim 1, wherein thedehumidifier and the heating element are arranged parallel to oneanother in the air circuit.
 9. The dishwashing machine as claimed inclaim 1 wherein the air circuit is a closed and/or open circuit andflows through a washing compartment of the dishwashing machine.
 10. Thedishwashing machine as claimed in claim 1 wherein the water inflowcomprises at least one heating element, which is arranged between thedehumidifier and the washing compartment
 11. The dishwashing machine asclaimed in claim 1 wherein the water inflow connects to washing arms ofthe dishwashing machine from a freshwater supply.
 12. The dishwashingmachine as claimed in claim 1 wherein the air of the air circuit entersan interior of the dehumidifier via a distributor arranged in thedehumidifier and emerges from the dehumidifier via an orifice arrangedabove a water level.
 13. The dishwashing machine as claimed in claim 1wherein the water of the water inflow enters the interior of thedehumidifier via an inflow and emerges from the interior of thedehumidifier via an outflow.
 14. The dishwashing machine as claimed inclaim 1 wherein during the operation of the air circuit, the water ofthe water inflow fills the dehumidifier up to a level (H) and, inparticular, flows through it slowly.
 15. The dishwashing machine asclaimed in claim 14 wherein the distributor is arranged below the waterlevel.
 16. A method for the washing and drying of a batch which isarranged in a washing compartment comprising at least a washingoperation, a rinsing operation and a drying operation which are carriedout in succession in the washing compartment and wherein, during thedrying operation, an air stream for drying the batch is generated withinthe washing compartment with the air circulating in a closed air circuitand being dehumidified in a dehumidifier by means of a supply of rinsingwater for the rinsing operation which is contained in said dehumidifier.